Option b is the correct answer. The first Sultan of Delhi to introduce regular coins and declare Delhi as the capital of his empire was Iltutmish. Iltutmish introduced the silver tanka and the copper jital coins. His new bimetallic coinage system addressed the silver shortage issue and became the foundation for coinage during the Sultanate period. He also moved the capital to Delhi from Lahore after dethroning his predecessor Aram Shah in 1211 Itutmish shifted the capital to Delhi due to its strategic location, central to his expanding empire. This relocation facilitated better administration and defense, solidifying his rule and contributing to the growth of the Delhi Sultanate. Important Tips Iltutmish (1211 - 1236 AD): Iltutmish, originally named Samshuddin Illiyas, reigned from 1211 to 1236 . He was son in law of Qutbiddin Aibak. Iltutmish's strategic policy toward the Mongols prevented an attack by Genghis Khan. He denied support to Khwarazm Shah Jalaluddin from Central Asia. He transferred the capital from Lahore to Delhi. Iltutmish accomplished the construction of the Quwwat-ul-Islam Mosque and the Qutub Minar. He initiated the feudalistic system of Iqtha/Iqthadari. Iltutmish formed the Chahalgani, a pact involving forty Muslim nobles. He introduced the coinage system of the Delhi Sultanate, which included the Tanka (silver coin), Biranz (bronze coin), and Jittal (copper coin). Iltutmish nominated his daughter, Raziya, as his successor. He provided patronage to Minas-ur-Siraj, the author of "Minaj-usSiraj." Iltutmish quelled internal rebellions by Rajputs in Gwalior, Ranthambor, Ajmer, and Jalore. He successfully managed challenges posed by Nasiruddin Qabacha in Lahore and Multan, and thwarted a conspiracy by Alivardan, the governor of Bengal.